Gawk

If you are like many computer users, you would frequently like to
make changes in various text files wherever certain patterns appear,
or extract data from parts of certain lines while discarding the rest.
To write a program to do this in a language such as C or Pascal is a
time-consuming inconvenience that may take many lines of code.
The job is easy with awk, especially the GNU implementation: gawk.

The awk utility interprets a special-purpose programming language
that makes it possible to handle simple data-reformatting jobs with
just a few lines of code.